C++学习 boost学习之-Synchronization

要点：

1 boost提供了如下lock模板类，以mutex类型作为模板参数

Class templatelock_guard

Class templateunique_lock

Class templateshared_lock

Class templateupgrade_lock

Class templateupgrade_to_unique_lock

Mutex-specific classscoped_try_lock

2 boost提供了如下mutex类型，分别用于上面的lock模板类的参数

Class mutex

Typedef try_mutex

Class timed_mutex

Class recursive_mutex

Typedef recursive_try_mutex

Class recursive_timed_mutex

Class shared_mutex

3 condition 类型

Class condition_variable

Class condition_variable_any

Typedef condition

4 仅初始化一次问题

 

<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">once</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>

<span class="identifier">boost</span><span class="special">::</span><span class="identifier">once_flag</span> <span class="identifier">f</span><span class="special">=</span><span class="identifier">BOOST_ONCE_INIT</span><span class="special">;</span>

<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Callable</span><span class="special">></span><span class="keyword">void</span> <span class="identifier">call_once</span><span class="special">(</span><span class="identifier">once_flag</span><span class="special">&</span> <span class="identifier">flag</span><span class="special">,</span><span class="identifier">Callable</span> <span class="identifier">func</span><span class="special">);</span>

<span class="keyword">void</span> <span class="identifier">call_once</span><span class="special">(</span><span class="keyword">void</span> <span class="special">(*</span><span class="identifier">func</span><span class="special">)(),</span><span class="identifier">once_flag</span><span class="special">&</span> <span class="identifier">flag</span><span class="special">);</span>

两个函数，一个flag，用于程序中仅调用一次func

5 Barriers

<span class="keyword">class</span> <span class="identifier">barrier</span><span class="special">{</span><span class="keyword">public</span><span class="special">:</span>    <span class="identifier">barrier</span><span class="special">(</span><span class="keyword">unsigned</span> <span class="keyword">int</span> <span class="identifier">count</span><span class="special">);</span>    <span class="special">~</span><span class="identifier">barrier</span><span class="special">();</span>    <span class="keyword">bool</span> <span class="identifier">wait</span><span class="special">();</span><span class="special">};</span>

障碍是一个同步点，在wait的地方，必须count个线程都执行到该位置，才开始wait后面的内容；

6 futures

应用场合是：一个线程发出命令，另外一个线程执行命令，发出命令线程通过future获得命令的执行结果；详细内容参考分布式网络编程内容《面向模式的软件体系结构卷2》

相关的类有boost::promise or a boost::packaged_task；

总结，同步内容很多，详细参考boost文档；该内容很实用；